This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Application No. 2002-146852 filed on May 21, 2002.
This invention generally relates to a vehicle door apparatus.
A known vehicle door apparatus for opening and closing a vehicle door includes a drive mechanism for driving the door from an open state to a closed state, and a closure mechanism including a striker provided at the vehicle body and a latch provided at the door for engaging with the striker so as to lock the door. The closure mechanism drives the latch to engage with the striker being positioned within a region where the striker is engageable with the latch when the drive mechanism drives the door in a closing direction, and shifts the latch to a final locked position. The vehicle door apparatus also includes a control mechanism for controlling operations of the drive mechanism and the closure mechanism in accordance with a door closing command. Further, the vehicle door apparatus includes a switch that is turned on when it is detected that the striker is positioned within the region where the striker is engageable with the latch. The control mechanism of the door apparatus deactivates the drive mechanism when the switch is turned on and at the same time activates the closure mechanism.
A control method according to the above-mentioned control mechanism is shown in FIG. 9A. The drive mechanism is operated to produce the output in accordance with the door closing command. The door is then moved in a closing direction. When the door is closed to a point where the striker is positioned within the region where the striker is engageable with the latch (hereinafter referred to as xe2x80x9ctemporary closed statexe2x80x9d) and thus the switch is turned on, the drive mechanism is stopped to operate and the closure mechanism is activated as shown above.
The door and the vehicle body where the door is attached may have the respective distortion. In a final stage of the door closing operation, a reaction force against the door closing direction is generated when the door and a portion of the vehicle body to be attached to the door become in contact with each other, due to the respective distortion of the door and the vehicle body. In addition, a seal member provided between the door and the corresponding vehicle body portion may generate the reaction force due to a compression of the seal member. Thus, when the door is closed by the drive mechanism and placed in the temporary closed state, the above-mentioned each reaction force may affect the door to return in an opening direction. When the reaction force is large, the door may return in the opening direction immediately after the door is placed in the temporary closed state.
According to the known vehicle door apparatus mentioned above, the drive mechanism is stopped to operate when the door becomes in the temporary closed state. The temporary closed state may be thus cancelled as the door returns in the opening direction before the door is placed in the final locked position by the closure mechanism. As a result, the switch is turned off and therefore an additional cycle such as repeating the operation of the drive mechanism is required for obtaining the temporary closed state (shown in FIG. 9B). An extra time is required to completely close the door and therefore, the door closing efficiency requires to be improved.
In order to solve the above-mentioned problem, as shown in FIG. 10, it is considered to delay the drive mechanism to stop so that the door is moved in the closing direction by the output of the drive mechanism until the closure mechanism is ready to operate. In this case, however, the door may suffer another distortion and further, a clutch, a motor and a drive circuit of the drive mechanism may receive the harmful effect. Precisely, abnormal noise or heat is produced since the clutch may slip widely and the abrasion of the clutch is increased. In addition, the heating value of the motor or the drive circuit is increased and thus the durability of the door apparatus may be decreased.
In light of the foregoing, a need exists for a vehicle door apparatus which addresses at least the foregoing drawback associated with other known vehicle door apparatus.
Thus, a need exists for a vehicle door apparatus which can perform a smooth door closing operation without applying an inappropriate force to the door.
According to an aspect of the present invention, a vehicle door apparatus includes a drive mechanism for driving the door from an open state to a closed state, and a closure mechanism including a striker provided at the vehicle body and a latch provided at the door for engaging with the striker so as to lock the door. The striker is positioned within a region where the striker is engageable with the latch when the drive mechanism drives the door in a closing direction. The latch is driven to engage with the striker and shifted to a final locked position by the closure mechanism. In addition, the vehicle door apparatus includes a control mechanism for controlling operations of the drive mechanism and the closure mechanism based on a door closing command, a detection means for detecting the striker to be positioned within the region where the striker is engageable with the latch and a drive force decreasing mechanism provided in the control mechanism for decreasing an output of the drive mechanism after the detecting means detects that the strikes is positioned within the region where the striker is engageable with the latch.